The European Union's top food safety agency said on Thursday cloned animal products may not be safe and further study was needed.

"It is clear there are significant animal health and welfare issues for surrogate mothers and clones that can be more frequent and severe than for conventionally bred animals," Vittorio Silano, chair of EFSA's Scientific Committee, told reporters.

 "For cattle and pigs, food safety concerns are considered unlikely. But we must acknowledge that the evidence base is still small. We would like to have a broader data base and we need further clarification."    

"That has been one of the challenges throughout this work," he added.

In its initial response to the issue of cloning -- which many consumer and religious groups strongly oppose -- EFSA said in January that cloned animals could be safe to eat. It also said it saw "no environmental impact from animal cloning".

But when asked if cloned products such as meat and dairy would be safe for people to buy in European supermarkets, Dr. Dan Collins of EFSA said: "There are possible concerns ... there is an impact of animal health and welfare on food safety. We need more data."         

In March 2007, the European Commission -- the EU's executive arm -- asked the Bologna-based food agency to investigate the merits of cloning -- which takes cells from an adult and fuses them with others before implanting them in a surrogate mother.

The move by Brussels was prompted after the US Food and Drug Administration (FDA) gave its backing to meat and milk products from cloned cattle, pigs and goats.

Hundreds of animals have been cloned mainly in the United States, while Britain and Germany are leading the push to allow cloned products to be sold in the EU and London has already confirmed that it has imported a cloned offspring.

Advocates of livestock cloning say the technology will help produce more milk and lean, tender meat by creating more disease-resistant animals. They insist it is perfectly safe.

But opponents say scientists don't know its effects on nutrition and biology. With or without EFSA's backing, the EU executive says consumers will need to be convinced and intends to carry out an EU-wide consumer survey on the issue in September.

More than half of shoppers in a recent survey by the International Food Information Council said they were unlikely to buy food made from cloned animals.

The largest US dairy producer and distributor, Dean Foods, said last month that it would not sell milk from cloned animals due to consumer concerns. - Reuters